A crystalline lens surgically and anatomically includes an anterior capsule, a cortex, a nucleus, and a posterior capsule, but a cataract clouds these constituent elements. The cataract is an adult disease that rapidly increases in persons over the age of 60, and significantly increases in progression and degree of clouding, and the cataract is the most common disease as the reason of blindness.
Regarding the treatment of the cataract, there is only a surgical method of removing the crystalline lens with the clouding, and inserting an artificial transparent crystalline lens, which is made artificially, onto the location from which the crystalline lens has been removed. At present, a surgical method, which is most widely used for cataract surgery, is a surgical method of inserting the artificial crystalline lens into the capsule after phacoemulsification, and the procedure thereof is widely carried out in the sequence of keratotomy, anterior capsulotomy, phacoemulsification and aspiration, decortication, and insertion of the artificial crystalline lens.
The perfectly circular anterior capsulotomy has the following meanings in the cataract surgery.
First, when the anterior capsule is removed as a single piece, the anterior capsule does not become an obstacle and does not hinder a subsequent surgical operation.
Second, force, which is transferred to the capsule during the surgical operation, is uniformly distributed to disperse force that is transferred to a ligament of the crystalline lens, thereby preventing dislocation of the crystalline lens during and after the surgical operation.
Third, the circular anterior capsulotomy allows the eye to have a stable close system, thereby preventing damage to the posterior capsule.
Fourth, the circular anterior capsulotomy increases physical stability while manipulating the capsule during a surgical operation (separation of nucleus, nucleus splitting, a manipulation of the crystalline lens, and the like), thereby reducing surgical complications.
Fifth, by preventing shrinking and clouding of the capsule after the surgical operation, it is possible to prevent a deterioration in eyesight that may occur again after a successful surgical operation.
In addition to the circular shape, the size is also an important factor that determines success and failure during the anterior capsulotomy. In general, the size of the capsulotomy is slightly smaller than a size of an optical unit of the artificial crystalline lens. If the size of the capsulotomy is greater than the size of the optical unit of the artificial crystalline lens, there may occur dislocation of the artificial crystalline lens, iridentropium, deviation, and the like which may cause a deterioration in eyesight, and in a serious case, reoperation may be carried out. In addition, if the size of the capsulotomy is excessively small, shrinking of the capsule occurs, which blocks a visual axis and causes a deterioration in eyesight and causes clouding of the anterior capsule and the posterior capsule, and whereby an additional surgical operation is required, and the shrinking of the capsule causes dislocation of the artificial crystalline lens, which may cause a deterioration in quality of eyesight after the surgical operation. Korean Patent Application Laid-Open No. 2011-0084887 discloses a cystitomy device.
Recently, the importance of the anterior capsulotomy with a perfectly circular and appropriate size is further increased as use of multifocal artificial crystalline lenses for correcting presbyopia and use of artificial crystalline lenses for correcting astigmatism are increased. In the case of the artificial crystalline lens, the complications after a surgical operation, such as abnormality in position, or clouding of the posterior capsule, have a greater effect on eyesight than a short focal length artificial crystalline lens, and an additional manipulation itself for solving the complications may cause a deterioration in performance of the artificial crystalline lens.
Surgeons with much experience usually perform the anterior capsulotomy based on a size of a cornea of a patient and a size of an enlarged pupil. However, the size of the cornea differs from patient to patient, and the size of the enlarged pupil is also not uniform, such that a final size is not uniform. Because the shape of the anterior capsulotomy depends only on the experience and the surgical technique of the surgeon, it is very difficult to perform the perfectly circular anterior capsulotomy. In addition, if the size and the shape of the anterior capsulotomy are not perfect, an additional surgical operation needs to be carried out in order to adjust the size of the capsule of the crystalline lens after inserting the artificial crystalline lens, which causes a waste of time and efforts.
As described above, because the anterior capsulotomy is a very precise surgical operation, there is a need for a device capable of guiding a precise size and a position during the anterior capsulotomy.